SurfaceView 和 ANativeWindow

Question

I have a question regarding creation of a SurfaceView and subsequently getting a ANativeWindow from it.

1. Is it proper to do
   
   mSurfaceView = new SurfaceView(this); in:
   
   
   • onCreate()
   • onStart()

Reason for asking: as I understand it the SurfaceView will get destroyed when we lose focus (something else covers up the entire screen) so we will need to re-create it every time we gain focus (onStart() is executed). Or does the SurfaceView remain dormant and reusable?

1. Moving on, now I would like to create a native window from the above-mentioned surface (in native code). Is it proper to do
   
   ANativeWindow* newwindow = ANativeWindow_fromSurface(jniEnv, joSurface) in:
   

   • onSurfaceCreated_native(..., jobject surface)
   • onSurfaceChanged_native(..., jobject surface)

Reason for asking: onSurfaceChanged seems to be always called after onSurfaceCreated so we have a choice as to when to create the native window. On one hand, it appears logical to do this in onSurfaceCreated , but the two jobject surface appear to be referencing different objects! (As checked by creating a weak global ref to surface in onSurfaceCreated and checking it against both NULL and surface in onSurfaceChanged, see code below)

onSurfaceCreated_native(JNIEnv env, ... ,jobject surface) {
myWeakObjectGlobal = env->NewWeakGlobalRef(surface);
}

onSurfaceChanged_native(JNIEnv env, ... ,jobject surface) {

if (env->IsSameObject(surface, myWeakObjectGlobal)) {
    LOGW("onSurfaceChanged_native: new surface is SAME as old surface");
} else {
    LOGW("onSurfaceChanged_native: new surface is DIFFERENT as old surface");
}

if (env->IsSameObject(NULL, myWeakObjectGlobal)) {
    LOGW("    furthermore, old surface is NULL");
} else {
    LOGW("    furthermore, old surface is NOT null");
}

}

Therefore, if there are indeed two distinct surface objects being sent into onSurfaceCreated and onSurfaceChanged, then we want to use the freshest one and not hang on to a stale surface reference, and consequently do ANativeWindow_from_Surface in onSurfaceChanged.

I would really appreciate it if someone could shine some light on this issue for me.

Answer 1

您是否尝试过使用android.view.Surface而不是android.view.SurfaceView ？